My Tdi sometimes blows white smoke out the exhaust. I also have to top up coolant quite regularly. The advice I got so far is timing that is incorrect and over fuelling. What is your take on this? – grant ( boksburg) ed – If the vehicle is over fuelling then you would have excessive black smoke leaving the exhaust because of unburned fuel. The fact that you have to top up the coolant regularly makes me believe that you have a blown head gasket between a water port and exhaust valve which blows steam out from the exhaust.